Topic 2, Electromagnetic Compatibility

Question 1

You are placing Category 6 unshielded twisted-pair (UTP) in cable tray down a hallway past the elevator mechanical room. What action should you take to avoid effects of electromagnetic interference (EMI)?

A. Provide a minimum separation of 1194 mm (47 in)
B. Provide a minimum separation of 2060 mm (81 in)
C. Require the architect to install metallic foil shielding on the mechanical room walls
D. Provide RMC/IMC (rigid metallic conduit/intermediate metal conduit) through all areas within 4.6 m (15 ft) of the mechanical room

Answer 1

A. Provide a minimum separation of 1194 mm (47 in)

Question 2

You have discovered a common mode current on the metallic cable sheaths of your building riser cables. What is the MOST likely cause for you to investigate?

A. Lack of cable protection
B. Two separate and distinct ground references
C. Improper secondary protection
D. Improper physical protection of cable
E. Improper placement and/or termination of cables

Answer 2

B. Two separate and distinct ground references

Question 3

What is the recommended MINIMUM separation of unshielded twisted-pair (UTP) cables from fluorescent light fixtures?

A. 77 mm (3 in)
B. 30 mm (5.12 in)
C. 203 mm (8 in)
D. 324 mm (12.75 in)
E. 483 mm (19 in)

Answer 3

B. 30 mm (5.12 in)

Question 4

You are required by architectural design to place UTP cables in the same space as unshielded power lines. How should you proceed with the placement of your cables?

A. Require the architect/electrical engineer to place shielding in the space before your UTP is placed.
B. You should provide a minimum separation of 610 mm (24 in).
C. You should provide a minimum separation of 229 mm (9 in).
D. You should provide a minimum of two 101 mm (4 in) RMC.

Answer 4

B. You should provide a minimum separation of 610 mm (24 in).

Question 5

Which of the following is NOT a form of signal coupling between two (2) circuits?

A. Conductive
B. Inductive
C. Reactive
D. Capacitive
E. Electromagnetic

Answer 5

C. Reactive

Question 6

A common mode (CM) signal can be converted to a differential mode (DM) signal as a result of a(n):

A. Unbalanced circuit
B. Grounded circuit
C. Poorly timed signal
D. Improper dielectric material

Answer 6

A. Unbalanced circuit

Question 7

The electromagnetic spectrum of visible light lies in the ___________ frequency range of the spectrum.

A. 1 GHz
B. 100 GHz
C. 10 THz
D. 1 PHz
E. 100 PHz

Answer 7

D. 1 PHz

Question 8

The potential for ______ occurs when devices or systems share a common electromagnetic environment and their operational frequencies overlap.

A. Electromagnetic interference (EMI)
B. (EMC)
C. Radio frequency interference (RFI)
D. Fast transients
E. Electrostatic discharge (ESD)

Answer 8

A. Electromagnetic interference (EMI)

Question 9

Which of the following is an undesirable electromagnetic effect on a device(s)?

A. (EMC)
B. Electromagnetic interference (EMI)
C. Radio frequency interference (RFI)
D. Fast transients
E. Electrostatic discharge (ESD)

Answer 9

B. Electromagnetic interference (EMI)

Question 10

During a site survey you notice that several CRT displays in the vicinity of the engineering copy center have sporadic visual distortion. What is the MOST likely cause?

A. Electromagnetic interference (EMI)
B. Radio frequency interference (RFI)
C. (EMC)
D. Fast transients
E. Electromagnetic discharge (ESD)

Answer 10

A. Electromagnetic interference (EMI)

Question 11

The ability of a device to withstand electromagnetic disturbances from another device is:

A. Electromagnetic interference (EMI)
B. Radio Frequency Interference (RFI)
C. (EMC)
D. Fast transients
E. Electrostatic Discharge (ESD)

Answer 11

C. (EMC)

Question 12

Which of the following is NOT a source of electromagnetic interference (EMI)?

A. Copiers -
B. Transformers -
C. Incandescent lights -
D. Fluorescent lights -
E. Electrical power supply cable

Answer 12

C. Incandescent lights -